Fuse block



June 20, 1939. M. G. DAHL FUSE BLOCK Filed June 15, 1935 INVENTOR MAGNUS G. DAHL BY HIS ATTORNEYS Patented June 20, 1939 PATENT OFFICE FUSE BLOCK Magnus G. Dahl, West Hartford, Conn, assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application June 15, 1935, Serial No. 26,818

7 Claims.

This invention relates to fuse blocks. More particularly it relates to fuse blocks for fuses of the screw plug type.

In many instances fuse blocks are used in which fuses of opposite polarity are located next to each other. It is desirable under such conditions that the receptacles .or sockets or screw shells of the fuses be separated from each other by a positive insulating medium.

It is an object of my invention to provide a positive insulating medium between adjacent screw plug type of fuse receptacles.

Under some conditions. it is not necessary for a positive insulating medium or body to be placed between fuses mounted upon thesame fuse block.

It is an object of my invention to provide a removable fuse separating barrier adapted to be positioned between fuse receptacles .or not, so that the same block may be used either when adjacent fuses are tobe of opposite polarity, or when adjacent fuses need not be separated by a positive insulating medium.

A further object of my invention is to provide a removable barrier on the fuse block between the fuse receptacles, which barrier will be held in position by the screw shells of the fuse receptacles and also, indirectly, by the same means which hold the fuse receptacles to the fuse block.

Other objects and advantages of my invention 3( will become apparent as it is described in connection with the accompanying drawing.

In the drawing:- I

Figure 1 is a plan view of my invention.

Figure 2 is a longitudinal vertical section view taken on line 2-2 of Figure 1.

Figure 3 is a longitudinal vertical section view taken on line 3-3 of Figure 1.

Figure 4 is a transverse section view of my invention, taken on line 4-4 of Figure 1.

Referring to the drawing it will be noted that the fuse block or base 10 is formed of insulating material. customarily such fuse blocks are made of porcelain but, obviously other insulating materials may be used. The fuse block may be rectangular in shape with rounded corners and with side walls perpendicular to the face of the block. The block may be hollowed out from the bottom to form a large recess. At opposite sides of the block on its top face are seated conventional screw shells or fuse receptacles l2 and I4 into which may be screwed conventional screw type plug fuses. Each of the fuse receptacles i2 and I4 has in its side wall adjacent the bottom of the receptacle an aperture (see [21!) facing toward one end of the block and receiving a wire terminal-plate. These terminal plates Iiiand l3 are identical and may be stamped from sheet metal. Each plate has a portion lying outside of thereceptacle and a portion within the receptacles lying upon the bottom thereof. Referring 5 to the plate it there is-provided in the inside portion a large round aperture 28 through which the shank of a screw 22passes freely so that there is no electrical connection therebetween. Still referring to terminal plate [5, an insulating 10 disc or washer 24 lies on said plate so as to insulate'it from the head of the screw 22. In order that the screw shell [2 shall not have a direct electrical connection with the screw 22 there is provided in the center of the bottom of the shell 15 an aperture through which the shank of the screw passes, the aperture being larger than the shank of the screw so that the screw will be out of electrical contact with theshell. Thus the head of this screw 22 affords a central contact 20 for the fuse receptacle l2, and may be engaged by the. center contact of a fuse plug as the fuse plug is screwed into the shell 12. Preferably the bottomof the screw shell around the edge of the aperture is extruded upwardly.

The portions of the wire terminals l6 and 58 which extend outside of the fuse receptacles may each havean aperture formed in it with the metal around theaperture extruded and screw threaded for the reception of wire terminal screws 26, 28. 30 The extruded portion may extend down into a recess in the top of the base or block and thus assist in holding the terminal in position.

Within the recess of the fuse block or base l0 there is provided a double pole switch mecha- 35 nism, comprising two pairs of stationary contacts 30, 32 and 34, 36, each pair being bridged by a movable contact 38, 40 which is mounted upon an insulating plate 42 that is rectilinearly movable between the adjacent surfaces of each pair 40 of stationary contacts by a handle (not shown) in a plane parallel to the top of the fuse block or base. One of the stationary contacts 30 may be secured in position by and electrically connected with the central screw 22. The switch 45 mechanism per se forms no part of this invention and therefore need not be described in detail.

In the embodiment of the invention which I have shown there are provided two fuse receptacles and two sets of stationary switch contacts so that the device forms what is commonly known as a double pole construction. Thus the two fuse receptacles will be required to carry current of opposite polarity. Thus it is desirable 55 to provide positive insulating means between the shells of the two receptacles.

For this purpose I provide a barrier 44 of suitable insulating material positioned between the fuse receptacle I2 and I4, and I provide in the upper face of the insulating fuse block a shallow well 45 into which the bottom portion of the barier fits. The bottom portion of the barrier 44 has straight end walls 44a, parallel to the ends of and perpendicular to the surface of the block. The side walls 44s, also, of the bottom portions of the barrier are perpendicular to the surface of the block but are arcuate. The centers of the arcs lie in the central axes of the fuse receptacles l2 and I4. However the radius of curvature of these arcs or curved walls is less than the radius of curvature of the fuse receptacles, so that the curved Walls of the bottom of the barrier lie under the bottoms of the fuse receptacles.

The upper portion of the barrier 44 has plane end walls in extension of the walls 44a of the bottom. The side walls 441: of the upper part of the barrier are curved, the radius of curvature of these walls being slightly greater than the radius of curvature of the fuse receptacle. The centers of the arc of curvature lie in the axes of the fuse receptacles when those receptacles are situated in assembled position.

Thus shoulders 44.2 are provided at each side of the barrier which shoulders underlie the fuse receptacles l2 and M respectively. Thus it will appear that as the device is assembled, the barrier will be placed within the well and then the fuse receptacles l2 and I4 will be screwed in position, with the end portions of their bottom bases overlying the shoulders of the barrier and thus holding the barrier securely in position.

It is an advantage to have the barrier removable from the base for the reason that the barrier need not be used when conditions do not require it, such as when the base is to be used in constructions which do not have fuses of opposite polarity upon it. Also it is an advantage not to have to mold the barrier and the fuse base as one piece. It is an added advantage to be able to mold a uniform base which is adapted for use under varying conditions and to mold separately an insulating barrier which may be used in connection with the base wheneverconditions require it.

Many changes in form within the scope of my invention will occur to those skilled in the art. I therefore do not limit myself to the specific form of the embodiment shown.

I claim:-

1. In combination, a base of insulating material, a pair of screw shell fuse receptacles, means to secure said receptacles on said base, said base having a well between said receptacles, a barrier formed separately from the base and seated in said well, said barrier having portions underlying said receptacles to retain said barrier irremovably in place.

2. In combination, a base of insulating material, a pair of screw shell fuse receptacles, means to secure said receptacles on said base, said base having a well between said receptacles, a barrier formed separately from the base and having an enlarged integral base portion seated in said well, said base portion underlying said receptacles whereby the barrier is held in place.

3. In combination, a base of insulating material, a pair of screw shell fuse receptacle contacts, means to secure said receptacle contacts on said base, and a barrier formed separately from said base and seated thereon between said receptacle contacts, said barrier having portions underlying said receptacle contacts whereby the barrier is held in place.

4. In combination, a base of insulating material, a pair of screw shell fuse receptacle contacts, means to secure said. receptacle contacts on said base, and a barrier formed separately from said base and seated thereon between said receptacle contacts, said barrier being engaged and held in position by said receptacle contacts.

5. In combination, a base of insulating material, a pair of screw shell fuse receptacles, a barrier formed separately from said base and positioned between said receptacles, and central conducting means within said receptacles and insulated therefrom securing said receptacles and said barrier irremovably upon said base.

6. In combination, a base of insulating material, a pair of screw shell fuse receptacles, a barrier formed separately from said base and positioned between said receptacles and having portions underlying said receptacles, and common means to secure said receptacles and said barrier irremovably upon said base.

'7. In combination, a base of insulating material, a pair of screw shell fuse receptacles, a barrier formed separately from said base and positioned between said receptacles and having portions underlying said receptacles, and central conducting means within said receptacles and insulated therefrom securing said receptacles and said barrier irremovably upon said base.

MAGNUS G. DAHL. 

